Biophysical bases and the physiological implications of the posttranslational regulation of the Arabidopsis thaliana K+ channel AKT2

AKT2是模式植物拟南芥中唯一的钾离子通道。这种电压门控K+通道具有特殊的门控特性，其受到翻译后修饰（例如磷酸化）的强烈调节。当非磷酸化AKT2的行为作为一个内向整流钾通道介导的K+摄取。然而，在其磷酸化形式中，AKT2被锁定打开，因此可以在质膜上双向运输K+。虽然最近的出版物提供了第一次洞察到独特的门控的AKT2，其调节以及这种调节的生理意义仍然是一个问题的debate.This建议，这是基于最近的三个自己的出版物，旨在澄清某些方面的调节活动的AKT2。计划中的工作结合了生物物理学、分子生物学、植物生理学、生物化学和计算模拟方法。它涉及突变AKT2通道的产生及其在异源表达系统中的分析，表达突变AKT2通道的转基因植物的分析以及AKT2蛋白翻译后修饰的生物化学鉴定。这些实验的结果将通过计算机模拟来补充，以模拟表达AKT2的植物细胞的电行为。不同方法的组合结果将允许开发关于独特K+通道AKT2的生理作用的详细图片。

AKT2 is unique among potassium channels in the model plant Arabidopsis thaliana. This voltage-gated K+ channel has exceptional gating properties that are strongly regulated by posttranslational modifications as e.g. phosphorylation. When nonphosphorylated AKT2 behaves as an inward-rectifying potassium channel mediating K+ uptake only. In its phosphorylated form, however, AKT2 is locked open and can therefore transport K+ in both directions over the plasmamembrane. Although recent publications provided first insights into the unique gating of AKT2, its regulation as well as the physiological implications of this regulation are still matter of debate.This proposal, which is based on three recent own publications, was designed to clarify certain aspects of the regulation of the activity of AKT2. The planned work combines biophysical, molecular biological, plant physiological, biochemical and computational simulation approaches. It involves the generation of mutated AKT2 channels and their analyses in heterologous expression systems, the analysis of transgenic plants expressing mutated AKT2 channels and the biochemical identification of posttranslational modifications at the AKT2 protein. The results of these experiments will be complemented with computational simulations to model the electrical behavior of plant cells expressing AKT2. The combined results of the different approaches will allow to develop a detailed picture on the physiological role of the unique K+ channel AKT2.